Vehicular body panel or component part and method for manufacturing same

ABSTRACT

A vehicular body panel or component part having a reinforcing backing plate reconciled to a part of a blank material at a position wherein a bending formation is implemented. The backing plate has one or more apertures formed in at least one lateral raw at a location equivalent to the position of the bending formation. When forming the blank material and the backing plate concurrently by a bending operation, the backing plate becomes intimately associated with the blank sheet to avoid the backing plate from locally separating from the blank material and from forming a gap relative thereto, with a resultant improved product quality.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to an improvement in a technique formanufacturing a vehicular body panel or component part.

2. Description of the Related Art

Japanese Patent Laid-Open Publication No. HEI-10-129527, for example,discloses a hood made of plastic resin material for use in anautomobile. The hood has a closed cross sectional structure which ismade of a product formed by a blow technique and which has an outer skinand a stiffener integral therewith. The outer skin has a main bodysection having a central portion extending in a widthwise direction of avehicle body, two side edge portions located at both sides of thecentral position and extending in a longitudinal direction of thevehicle body, and two connecting portions interconnecting the centralportion and the respective side edge portions. Each connecting portionincludes a reinforcement rib extending from the stiffener and depositedonto the outer skin. The reinforcement rib imparts increased rigidity tothe hood.

The presence of the hood made of the panel formed by plastic resinmaterial provides no difficulty in implementing the aforementioneddeposition during the forming operation of the plastic resin or in heatfusion of the two members (i.e., the reinforcement rib and the outerskin). However, the hood made of a steel panel obtained by bendingformation of the blank material is remarkably in wide use rather thanthe plastic panel. The hood made of the steel sheet encounters anotherissue different from the plastic panel. In particular, although it hasbeen a usual practice to employ a structure wherein a reinforcementplate, which is called as a backing plate, is attached to the steelpanel with a view to mounting a hinge or striker to the hood panel, thepresence of the backing plate formed of a curved plate encounters aproblem during mounting the backing plate to the hood. This problem ismore clearly described with reference to FIGS. 19A and 19B hereof.

As shown in FIG. 19A, a hood frame 201, formed by bending the steelblank material, and a steel backing plate 202, formed by bending thesteel sheet to conform to the curved profile of the hood frame 201, areprepared and are brought into contact with one another as shown by arrow{circle over (1)}.

As shown in FIG. 19B, an edge of the backing plate 202 is connected tothe hood frame 201 by a weld bead 203. Such a technique for connectingthe backing plate is widely used in known practice. In such a mountingtechnique, it is required to separately form the hood frame 201 and thebacking plate 202 separately by bending with a bending press or with abending machine, respectively, requiring two separate bending steps.

In many cases wherein the backing plate 202 has a larger thickness thanthat of the hood frame 201, there are some cases wherein the backingplate 202 has a smaller thickness than that of the hood frame 201. Ingeneral, the thickness of the hood frame 201 is not necessarily equal tothat of the backing plate 202. Since the steel plates suffer from springback phenomenon (i.e., a slight amount of restoring of the pressmaterial after press forming step) different in magnitude from oneanother depending on the thickness and the bending radius, there existsa slight difference in the curved shape between the hood frame 201 andthe backing plate 202. When reconciling or joining these components withsuch a difference in the curved shape, there exists an increasedtendency wherein a gap is produced at corners 204,205. Although thebacking plate 202 functions to locally reinforce the thin hood frame201, the presence of the gap results in a decrease in the reinforcementeffect.

In such a conventional manufacturing method described with reference toFIGS. 19A and 19B, the bending operation should be implemented in twosteps, with a resultant increase in the fabrication cost and a resultantdecrease in the reinforcement effect owing to the gap created betweenthe hood frame and the backing plate.

Next, when an outer side panel of raw material is blanked out from asingle stripped-shaped steel plate, a tail gate of the raw material isalso concurrently blanked out with a view to improving the productionyield with the use of a blanking method for a vehicle body, which isdisclosed, for example, in Japanese Patent Laid-Open Publication No.SHO-58-128231. In this method, when the outer side panel of the rawmaterial is sequentially blanked out from the steel plate, it is a usualpractice to blank out left and right symmetrical divided raw materialfor lower halves of the tail gate raw material from the steel plate at aportion thereof corresponding to a blanking area to form a door mountsection while blanking out left and right asymmetrical divided rawmaterial for upper halves of the tail gate raw material from the steelplate between the outer side panels of the raw material remaining sideby side. The two upper divided halves and the two lower divided halvesare welded to one another to obtain the tail gate of the raw material.Thus, it is well known to cut out a piece from a scrap portion, which isproduced during the blanking step of the vehicular body of the rawmaterial, for utilizing the piece to manufacture component parts of thevehicle body for thereby improving the yield of the raw material.

In the above method, the outer side panel of the raw material, which isdischarged from the blanking press, is then sequentially transferredthrough a drawing press, a trimming press and a piercing press toimplement the contracting step, the edge cutting step and the apertureforming step, respectively, to complete the formation of the outer sidepanel. On the other hand, the two divided lower halves of the rawmaterial and the two divided upper halves, both of which are dischargedfrom the blanking press, are transferred to a welding site in anotherroute, wherein these components are welded together to form the tailgate of the raw material.

Paying attention to the two divided lower halves and the two dividedupper halves, it is required for a specific transfer means, whichtransfers these components, to be located so as to extend from theblanking press, with a resultant factor which reduces a work spacearound the blanking press.

Further, it is necessary for these components to be adequately managedto prevent the components from getting mixed with other components orfrom being lost.

In addition, it is necessary to prepare a temporary stock space in thewelding site for the two divided lower halves of the raw material andthe two divided upper halves, and another temporary stock space in thewelding site for the completed tail gates of the raw material, occupyinga relatively larger space for the welding site.

When trying to improve the yield of the raw material by cutting out auseful piece from the scrap portion in the aforementioned manner, itbecomes necessary for a specific transfer means for the piece, a lossprotective measure for the piece and the welding site in a large spaceto be provided, with a resultant increased cost in the equipment as wellas an increase in an area for which the equipment is installed.

SUMMARY OF THE INVENTION

It is therefore a first object of the present invention to provide avehicular body panel or component part and a method of manufacturing thesame, which are capable of implementing a forming step in a single stepwithout forming a gap between a hood frame and a backing plate.

According to a first aspect of the present invention, there is provideda vehicular body panel or vehicular component part which comprises ablank material having a formed portion, and a backing plate reconciledwith the blank material and having at least one aperture located in aposition corresponding to the formed portion to accommodate physicalcharacteristics or properties of the blank material.

The presence of the aperture formed in the backing plate at the positioncorresponding to the formed portion of the blank material permits thebacking plate to preferably become integral or unitary with the blankmaterial. That is, when forming the two components by bending operation,there is no fear in the backing plate from locally separating from theblank material to form the gap, with a resultant increase in a finishingquality of the vehicular body panel or the vehicular component part.

The vehicular body panel involves, for example, panels such as an innerskin which forms a hood listed in the illustrated embodiment and, inaddition to this component part, a door, a floor and a roof which formpart of a vehicle body. In the event that the backing plate is used inthe inner skin, two backing plates are reconciled to both side edgeportions of the blank material in a widthwise direction of the vehiclebody, respectively.

According to a second aspect of the present invention, there is provideda method of manufacturing a vehicular body panel or a vehicularcomponent part, which comprises the steps of preparing a blank materialfor the vehicular body panel or a blank material for the vehicularcomponent part, preparing a backing plate formed with at least oneaperture to cope with a characteristic of the blank material,reconciling the backing plate to the blank material, and forming theblank material together with the backing plate.

The term “formation” used herein means a plastic deformation processingsuch as bending, contracting and expanding. Below discussions will bemade using “bending”, as an example. The employment of the backing plateformed with the aperture renders the blank material to be subjected tobending operation after the backing plate is reconciled thereto.Concurrent bending operation of the blank material and the backing plateenables the bending operation in a single step. In this event, it ispossible to reduce the cost for bending operation by half as compared tothe individual bending operations of the backing plate and the blankmaterial.

According to a third aspect of the present invention, there is provideda method of manufacturing a blank material for a vehicular body panel,which comprises the steps of preparing a first backing plate forreinforcing the vehicular body panel while feeding a strip-shaped sheetfor the vehicular body panel between upper and lower blanking diehalves, blanking the strip-shaped sheet by mating the upper blanking diehalf with the lower blanking die half relative to one another forobtaining a blank material for the vehicular body panel while obtaininga second backing plate, which has the same profile as the first backingplate, from a scrap portion, mounting the backing plate by locating andreconciling the first backing plate onto the blank material remainingbetween the upper and lower blanking die halves, and separating theupper blanking die half from the lower blanking die half for dischargingthe blank material with the backing plate.

The first backing plate is reconciled to the blank material in theblanking step. When it is required to reconcile the backing plate to theblank material in another site or in another step, although it isnecessary to perform the transfer of the blank material or to prepare astock place, the present invention makes it possible to render the blankmaterial to be manufactured in the upper and lower blanking die halvessuch that the transfer of the blank material or the stock place aredispensed with for thereby providing a compactness in the equipment.

The second backing plate is transferred to a position wherein the firstbacking plate is preliminarily located, and is then reconciled to asubsequent blank material. The backing plate is transferred within theupper and lower blanking die halves. That is, the backing plate, whichis cutout with the upper and lower blanking die halves, is reconciled tothe subsequent blank material without discharging the backing plateoutside. If the backing plate is discharged from the blanking site andis then transferred to the welding site, a specific transfer means isrequired. However, the transfer of the backing plate in the die halvesallows the specific transfer means to be dispensed with. In addition,since the backing plate is not discharged out from the die halves, thereis no fear of loss of the backing plate for thereby omitting acomponent-part management work for the backing plate.

In a preferred form, the backing plate reconciling means includes acaulking mechanism having a cavity segment remaining on one side and apunch remaining on the other side such that two sheets, which arecomposed of the blank material and the backing plate placed thereon, arelocated between the cavity segment and the punch to allow the punch tothrust toward the cavity segment for thereby caulking the two sheets.Accordingly, the caulking with the punch and the cavity segment allowsthe working efficiency to be improved.

BRIEF DESCRIPTION OF THE DRAWINGS

Certain preferred embodiments of the invention will be described indetail below, by way of example only, with reference to the accompanyingdrawings, in which:

FIG. 1 is an exploded perspective view of a hood according to apreferred embodiment of the present invention;

FIGS. 2A and 2B are schematic views illustrating a pair of backingplates formed with plural apertures and a blank material, to be preparedin a method of the present invention;

FIGS. 3A and 3B are schematic views illustrating the blank material withthe backing plates joined therewith at given positions, and the blankmaterial bent at predefined positions;

FIG. 4 is a perspective view illustrating the backing plate joined withthe blank material;

FIG. 5A is a cross sectional view taken along line 5A-5A of FIG. 4;

FIG. 5B is a cross sectional view illustrating a state in which thebacking plate and the blank material are bent;

FIG. 6 is a cross sectional view taken along line 6-6 of FIG. 4;

FIGS. 7A to 7D are schematic views illustrating the sequence ofvariation in shape of the aperture formed in the backing plate;

FIG. 8 is a schematic view illustrating various examples of the backingplates;

FIG. 9 is a perspective view of a damper housing;

FIG. 10 is a partially enlarged, cross sectional view of the damperhousing shown in FIG. 9;

FIG. 11 is a schematic view of a layout of a manufacturing apparatus forthe blank material of a vehicular body panel according to the presentinvention;

FIG. 12 is an enlarged cross sectional view taken along line 12-12 ofFIG. 11;

FIG. 13 is a cross sectional view illustrating a relationship betweenupper and lower blanking die halves and a strip-shaped plate;

FIG. 14A is a top plan view of the blank material;

FIG. 14B is a view illustrating an operation of the die halves wherein ascrap is cut out by the upper and lower die halves;

FIGS. 15A and 15B are views illustrating an operation of the backingplate reconciling means;

FIG. 16 is a view illustrating an operation of a backing plate transfermeans;

FIG. 17 is a view for illustrating a method of the present inventionwherein the blank material is blanked from the strip-shaped plate, thebacking is plate is cut out from a scrap and, subsequently, the backingplate is reconciled to the blank material;

FIG. 18 is a cross sectional view illustrating another preferredembodiment which is different from that of FIG. 16; and

FIGS. 19A and 19B are views illustrating a summary of a conventionalmanufacturing process for the vehicular body panel.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following description is merely exemplary in nature and is in no wayintended to limit the invention, its application or uses.

Referring now to FIG. 1, there is shown a hood 10 which is composed of adouble-layered structure wherein an outer skin 11 is piled on an innerskin 12. Both side edge portions of an upper surface of the inner skin12 have backing plates 13, 13, respectively. Brackets 14, 15 are fixedlysecured to each of the backing plates 13, 13 by means of a plurality ofbolts 16, respectively. The backing plates 13, 13 function to preventthe inner skin 12, which has a thin thickness, from being applied with alocalized load which causes the inner skin 12 to be locally deformed,thereby reinforcing the inner skin 12 around its side edge portions. Theinner skin 12, which is attached with the backing plates 13, 13, forms afirst preferred embodiment of a vehicular body panel according to thepresent invention.

Now, a fabrication method of the inner skin 12 as the vehicular bodypanel is described below with reference to FIGS. 2A to 3B.

As shown in FIG. 2A, a pair of plate-like backing plates 13, 13, each ofwhich has a plurality of apertures 17, are prepared.

Next, as shown in FIG. 2B, a plate-shaped blank material 18 is prepared.

Naturally, the backing plates 13, 13 and the blank sheet 18 may beconcurrently prepared or they may be prepared at different times. It isonly important that these components be prepared in time for a joiningor reconciling step described below.

FIGS. 3A and 3B are views for illustrating a sequence of the reconcilingstep and a bending step.

In FIG. 3A, the backing plates 13, 13 are reconciled to the blank sheet18 at respective predefined areas by means of an adhesive or welding,etc.

In FIG. 3B, the blank sheet 18 and the backing plates 13, 13 are bentalong a convex bending line 21 and a concave bending line 22, both ofwhich pass through the respective plural aperture rows 17, 17,respectively, thereby obtaining the inner skin 12 shown in FIG. 1. Abent portion of the blank sheet 18 is solid and free from aperture.

Now, the structure of the operation of the backing plate forming part ofthe present invention is described below in detail.

FIG. 4 shows a state wherein the backing plate 13 is reconciled to theblank sheet 18. For ease of explanation, the backing plate 13 is shownas having three apertures laterally formed in a row.

The flat blank sheet 18 with the backing plate 13, both of which areshown in FIG. 5A, are bent together as shown in FIG. 5B. This causeseach aperture 17 to be deformed in a V-shaped profile. Subsequently,action of the backing plate 13 with the plural apertures 17 and theblank sheet 18 is described below.

In FIG. 6, with a given data: b1=the width of the blank sheet 18, h1=theheight and Z1=the section modulus, the calculation is made using theformula Z1=(b1)·(h1)²/6.

The section modulus Z1 represents the magnitude of the bending rigidity,with an increase in the magnitude of the bending rigidity causing theblank material 18 to be hardly bent.

Similarly, with another given data: b2=the width of the backing plate13, d=the diameter of the aperture 17, n=the number of the apertures,h2=the thickness and Z2=the section modulus, the calculation is madeusing the formula Z2=(b2−n·d)·(h2)²/6.

The section modulus Z2 also represents the magnitude of the bendingrigidity, with an increase in the magnitude of the bending rigiditycausing the blank sheet 18 to be hardly bent.

When using the backing plate 13 as a reinforcing material, the backingplate 13 has an increased thickness. That is, the relationship inthickness is selected to meet h1<h2. In a case where the backing plate13 has a larger thickness than that of the blank sheet 18 and does nothave the plural apertures 17, then the relationship is expressed byZ1<Z2, the presence of the backing plate 13 disturbs the bendingformation of the blank sheet 18. In the case of h1<h2, consequently, itis desired to determine the value (n·d), namely, the diameter of theaperture 17 and the number of apertures 17, such that Z1=Z2 issatisfied. This process corresponds to the step of machining theapertures in the backing plate to meet the characteristic of the blanksheet (i.e., so as to adjust the section modulus (Z2) of the backingplate 13 relative to the section modulus (Z1) of the blank sheet 18).

Now, the case of h1≧h2 will be described. When the backing plate 13 hasa lower bending rigidity than that of the blank sheet 18, the backingplate 13 is readily bent with a resultant increased expansion orcontraction following the bending operation. With a further formation ofthe plural apertures 17 in such a backing plate 13, the backing plate 13has a reduced rigidity and an increased expanding and contractingproperty. As a consequence, the blank sheet 18 has an improved bendingfabrication property. Accordingly, even when the backing plate 13 has alower thickness than that of the blank sheet 18, the formation of theplural apertures 17 in the backing plate 13 is useful.

FIGS. 7A to 7D are views for illustrating the sequence of variations inthe shape of the aperture formed in the backing plate.

FIG. 7A shows a cross sectional view of the blank sheet 18 and thebacking plate 13 wherein the aperture 17 looks like a true circle 23 asviewed from above.

FIG. 7B shows a cross sectional view of the blank sheet 18 and thebacking plate 13 which are bent so as to protrude upward. In thisinstance, the aperture 17 has an elliptical profile 25 extending alongan axis 24 as viewed from above.

FIG. 7C shows a cross sectional view of the blank sheet 18 and thebacking plate 13 with a profile which protrudes downward. In thisinstance, the aperture 17 looks like an elliptical profile 27 extendingalong an axis 26 as viewed from above.

FIG. 7D shows a cross sectional view of the blank sheet 18 and thebacking plate 13 which are formed by an expansion forming or acontraction forming. In this instance, the aperture 17 has a profile,which is radially expanded outward, namely, an aperture 28 which has anincrease, radially expanded diameter.

In this manner, with such a deformation of the aperture 17, which ispreliminarily the circle 23, into the elongated elliptical profile 25which is expanded in a longitudinal (or lateral) direction, theelongated elliptical profile 27 which is expanded in a lateral (orlongitudinal) direction, or the aperture 28 with the increased diameter,it is to be noted that the backing plate 13 becomes intimate with theblank sheet 18 during the bending operation, namely, that the backingplate 13 is synchronized with the blank sheet 18 in the bendingoperation.

With the backing plate 13 without such an aperture 17, namely, with anaperture-less backing plate, the backing plate is hard to follow thebending and expanding sequences of the blank sheet 18 and is inevitablybrought into an undesirable ruptured state. With the backing plate 13formed with such an aperture 17, these issues are successfullyaddressed.

(a) to (i) of FIG. 8 show examples of various backing plates.

-   -   (a) shows a backing plate 13 having a single, large sized circle        aperture 17 a.    -   (b) shows a backing plate 13 having a plurality of small sized,        circle apertures 17 b formed in a zigzag pattern.    -   (c) shows a backing plate 13 having a plurality of small sized,        rectangular apertures 17 c formed in the zigzag pattern.    -   (d) shows a backing plate 13 having a plurality of oblong        apertures 17 d formed in a regular pattern.    -   (e) shows a backing plate 13 having a plurality of oblong        apertures 17 e formed in the zigzag pattern.    -   (f) shows a backing plate 13 having a plurality of elongated,        rectangular apertures 17 f formed in the regular pattern.    -   (g) shows a backing plate 13 having a plurality of elongated,        rectangular apertures 17 g formed in the zigzag pattern.    -   (h) shows a backing plate 13 having a plurality of apertures 17        h formed in a lattice pattern.    -   (i) shows a backing plate 13 having a single aperture 17 i        formed in an arbitrarily irregular profile.

As noted above, it is thus possible to freely determine the profile ofthe aperture and the number of the apertures to be formed in the bendingportion of the backing plate.

FIG. 9 illustrates a damper housing in a perspective view. The damperhousing 30 is a cylindrically shaped vehicular component part whoseupper portion is formed with a damper seat 31. A strut damper, whichforms a part of a wheel suspension unit, rests upon the damper seat 31.The damper housing 30 is constructed of a formed product including aplurality of steel plates piled to one another.

FIG. 10 is a partial cross sectional view of the damper housing, whereinthe backing plate 13 is piled to a cylindrical body 32 and the damperhousing is subsequently finished by press forming the same in a singlestep, featuring that the backing plate 13 has a reduced thickness withthe plural apertures 17, 17 formed at bending areas, namely, at cornersections to allow the backing plate 13 to become intimate with thecylindrical body 32 having a large thickness.

That is, during the press forming operation of the backing plate 13,which has the plural apertures 17, together with the cylindrical body32, the presence of the plural apertures 17 formed in the backing plate13 with a reduced thickness allows the backing plate 13 to be adequatelyexpanded and bent in synchronism with the formation of the cylindricalbody 32. As a result, the backing plate 13 is brought into an adequatelytight contact with the cylindrical body 32 throughout an entire,overlapped area.

In the illustrated embodiment described above, although the vehicularbody panel has been shown and described as applied to the example of theinner skin (stiffener) of the hood, the present invention may have anyother application unless the vehicular body panel includes a panel,which forms a part of a vehicle body, such as a door, a floor and roof,etc.

In the illustrated embodiment, further, although the present inventionhas been shown and described as applied to the example of the vehicularcomponent part composed of the damper housing, the present invention isnot limited to the component part of that kind and may have applicationto component parts of the other kinds provided that each of thecomponents parts includes a plurality of blank sheets (steel plates)which are piled to one another and constitute a product which is formedby the bending operation and which serves as an accessory component of avehicle. That is, although the present invention is specifically suitedfor the bending operation and the product formed by bending, the presentinvention may also be widely used in the “forming process” involvingforming of metal by contraction or expansion.

It will thus be seen that the present invention may be applied to thevehicular body panel in a broad sense or to the vehicular componentparts in a broad sense.

FIG. 11 shows a layout of a manufacturing apparatus, for the blank sheetof the vehicular body panel, according to the present invention. Themanufacturing apparatus 100 for the blank sheet of the vehicular bodypanel is arranged to firstly rewind a strip-shaped sheet 112 from a coil111 of metallic sheet, secondly passed through a leveler 113 for aflatness processing and finally passed through a blanking press machine,which includes main components such as upper and lower blanking diehalves 140 and 120, for punching treatment to obtain the blank sheet.

In FIG. 12, a lower die body 121 of a lower blanking die half 120includes a first die segment 122, a second die segment 123, a third diesegment 124, a fourth die segment 125 and a fifth die segment 126. Abacking plate transfer unit 130 is located between the third and forthdie segments 124 and 125 and includes a thruster plate 127 and athruster cylinder 128. A shutter plate 131, which forms part of thebacking plate transfer unit 130, is located between the fourth and fifthdie segments 125 and 126 for swinging movement about the center of a pin132. The fifth die segment 126 has a through-hole 133 formed in thevicinity of the shutter plate 131. A backing plate supporting plate 134is located in close proximity to a distal end of the through-hole 133and is moved upward or downward by a vertically moveable cylinder 135.The aforementioned backing plate transfer unit 130 is thus constructedof the thruster plate 127, the thruster cylinder 128, the shutter plate131 and the through-hole section 133 of the fifth die segment 126.

An upper die body 141 of an upper blanking die half 140 includes firstto fifth cutter segments 142 to 146 for shearing the workpiece in matingengagement with the aforementioned first to fifth die segments 122 to126, respectively. Stoppers 147, which are made of rubber, are locatedin the vicinity of the first, second and fifth cutter segments 142, 143and 146, respectively. The upper blanking die half 140 also includes apunch 148 located in a position opposing to the backing plate supportingplate 134 for caulking operation, and a gun unit 149.

The first to fifth cutter segments 142 to 146 are arranged to movedownward to a position indicated by a phantom line to perform theshearing of the workpiece. The upper blanking die half 140 may be heldstationary and the lower blanking die half 120 may be lifted up to shearthe workpiece.

Now, the operation of the aforementioned upper and lower blanking diehalves is described with reference to FIGS. 13, 14A and 14B.

In FIG. 13, under a condition wherein the thruster plate 127 isretracted and the shutter plate 131 is tilted downward while the upperblanking die half 140 waits in an upper position, the strip-shaped sheet112 is fed as the workpiece through between the upper and lower blankingdie halves 140,120 from a front side to a rear side as viewed in FIG.11. In addition, a first backing plate 151 is placed on the backingplate supporting plate 134 prior to the feeding of the strip-shapedsheet 112, subsequent to the feeding of the same or concurrently withthe feeding of the same.

FIG. 14A shows the blank sheet as viewed from above.

In FIG. 14B, as the upper blanking die half 140 is lowered to a bottomdead center, the first cutter segment 142 is caused to slide in contactwith the first die segment 122, thereby cutting out the sheet to form afirst scrap 152.

A large sized second scrap 153 is cut out from the sheet with the secondand fifth cutter segments 143,146, with the second scrap 153 beingconcurrently blanked out to form a second backing plate 154 with thethird and fourth cutter segments 144,145. That is, as shown in FIG. 14A,the sheet is blanked out to form the second scrap 153 in a conditionwherein the second backing plate 154 is left. Although the secondbacking plate 154 is identical in shape with the first backing plate151, the terminologies “first” and “second” are conveniently used with aview to providing an ease of differentiating these from one another.

In FIG. 14B, further, when the upper blanking die half 140 is kept atthe bottom dead center, the first backing plate 151 is brought intocontact with the blank sheet 155, thereby enabling a caulking step in amanner as will be described in detail with reference to FIG. 15.

In FIG. 14A, reference numeral 156 designates caulked portions whichallow the first backing plate 151 from being separated from the blankmaterial 155. In FIG. 14B, the blank material 155, to which the firstbacking plate 151 is joined, is then discharged rearward with respect tothe plane of the drawing when the upper blanking die half 140 is liftedupward.

An area, which is indicated by a symbol E1, is a punched out region andan area, which is indicated by a symbol E2, is a mounting place.

Now, a joining or reconciling method for reconciling the first backingplate 151 to the blank material 155 is described with reference to FIGS.15A and 15B.

In FIG. 15A, a backing plate reconciling means is constructed of acaulking mechanism 160. The caulking mechanism 160 includes a gun 149mounted to the upper blanking die half 140, a punch 148 attached to thegun 149, a vertically moveable cylinder 135 mounted to the lowerblanking die half 120, and a backing plate supporting plate 134connected to a distal end of a piston rod 161 of the cylinder 135. Thedistal end of the piston rod 161 is formed with an upwardly openingcavity segment 162.

In FIG. 15B, the actuation of the vertically moveable cylinder 135causes the piston rod 161 to move upward, thereby rendering the firstbacking plate 151 to be brought into abutting contact with a bottomsurface of the blank material 155. Then, the punch 148 is lowered withthe gun 149 to protrude into the cavity segment 162. The intrusion of apart of the first backing plate 151 into the cavity segment 162 rendersthe first backing plate 151, which is held in abutting contact with theblank material 155, to be reconciled to the blank material 155.

Now, the operation of the backing plate transfer unit 130 is describedwith reference to FIG. 16. That is, when the discharging operation ofthe blank material has been completed and the upper blanking die half140 remains in a waiting position, the succeeding operation isinitiated.

As seen in FIG. 16, the backing plate supporting plate 134 is loweredand the shutter plate 131 is caused to swing in a clockwise direction asshown by arrow {circle over (1)} such that an edge of the shutter plate131 fronts the through-hole 133. Then, the second backing plate 154,which is left on the lower blanking die half 120, is knocked up with thethruster plate 127. In this instance, the second backing plate 154 isdropped onto the shutter plate 131 and is transferred in slidingmovement as shown by arrow {circle over (2)} and passes through thethrough-hole 133 onto the backing plate supporting plate 134. The secondbacking plate 154, which is located on the backing plate supportingplate 134, is fed to a subsequent blank material 155. That is, thebacking plate transfer unit 130, which is composed of the thruster plate127, the thruster cylinder 128, the shutter plate 131 and thethrough-hole segment 133, functions to transfer the second backing plate154, which remains in the blanked out area E1, to the mounting area E2.

In this example, the second backing plate 154 is laterally transferredwithin a limited area between the upper and lower blanking die halves140,120 without being discharged outside, enabling the second backingplate 154 to be reconciled to the blank sheet 155. In the event that thescrap is removed from the upper and lower blanking die halves 140,120and is cut out again at another site to form another backing plate,although it is necessary to perform several steps involving the step ofcutting out the backing plate, the step of transferring the cut outbacking plate, the step of keeping possession of the backing plate, andthe step of avoiding loss of the backing plate, there is no need forworrying about the loss of the second backing plate 154 in theillustrated embodiment of the present invention.

As shown in FIG. 17, during movement of the strip-shaped plate 112 at apredefined constant speed in a direction as shown by arrow {circle over(3)}, first and second blank materials 155B, 155C are blanked out andsecond and third backing plates 154,164 are blanked out from the scrapof the first blank material 155B and the scrap of the second blankmaterial 155C, respectively. Subsequently, the second backing plate 154is waited and reconciled to the second blank sheet 155C, therebyobtaining the blank material 155A with the backing plate joined thereto.Reference numeral 156 designates caulked portions.

It will now be appreciated from the foregoing description that themethod of the present invention has the operating steps which aredescribed below.

In FIG. 13, the strip-shaped sheet 112 for the vehicular body panel isfed through the upper and lower blanking die halves 140,120 and, inaddition thereto, the first backing plate 151 is prepared forreinforcing the vehicular body panel. This is referred to as apreparation step.

In FIG. 14B, further, the upper blanking die half 140 is mated with thelower blanking die half 120 relative to one another for therebyobtaining the blank sheet 155 for the vehicular body panel whileobtaining the second backing plate 154, which has the same profile asthe first backing plate 151, from the second scrap 153. This is referredto as a blanking step.

In FIG. 14B, consecutively, the aforementioned backing plate 151 islocated on the blank sheet 155A and is reconciled thereto to provide ajoined structure. This is referred to as a backing plate mounting step.

In addition, the upper blanking die half 140 is removed from the lowerblanking die half 120, thereby expelling the blank sheet 155A with thebacking plate joined thereto from the die halves. This is referred to asan expelling step.

It will thus be seen that it is possible to manufacture the blank sheet155A with the backing plate at an improved efficiency by implementingthe preparation step→the blanking step→the backing plate mountingstep→the discharging step→the preparation step in a repeated sequence.

FIG. 18 shows another preferred embodiment of the present inventionwhich is modified from the unit shown in FIG. 16. The lower blanking diehalf 120 includes a palletizer 171 and a pusher 172 both of which form abacking plate feeder mechanism 170. The backing plate 173, which remainat the lower most position among the piled plural backing plates 173, issequentially pushed out as shown by arrow {circle over (4)} andtransferred through a through-hole 174 to be located on the backingplate supporting plate 134. The plural backing plates 173 may be cut outeither from the scrap or from a strip-shaped steel sheet.

With such a backing plate feeder mechanism 170, it is possible tomanufacture the blank sheet with the backing plate at an improvedefficiency by implementing the preparation step→the blanking step→thebacking plate mounting step→the charging step→the preparation step in arepeated sequence.

The backing plate reconciling means may involve the reconciling meanssuch as the caulking means, the reconciling means with the adhesive, themelting means with welding or other similar reconciling means and itdoesn't matter about the kind of the reconciling means.

Obviously, various minor changes and modifications of the presentinvention are possible in the light of the above teaching. It istherefore to be understood that within the scope of the appended claims,the invention may be practiced otherwise than as specifically described.

1. A vehicular part comprising: a blank material formed from a sheetmetal and having a bent portion; and a backing plate joined with theblank material and having a bent portion corresponding in position to,and bent along a same bending line as, the bent portion of the blankmaterial, the backing plate further having at least one aperture formedtherein at the bent portion thereof and located on the bending line. 2.The vehicular part according to claim 1, wherein the vehicular part isan inner skin forming part of a hood of a vehicle body, and the blankmaterial forms the inner skin.
 3. The vehicular part according to claim2, wherein the inner skin has opposite side edge portions extending in alongitudinal direction of the vehicle body, and the backing plate isdisposed on each of the side edge portions.
 4. The vehicular partaccording to claim 1, wherein the aperture is designed so as to make asection modulus of the backing plate equal to a section modulus of theblank material.
 5. The vehicular part according to claim 1, wherein asize of the aperture is selected so as to provide a desired sectionmodulus of the backing plate.
 6. The vehicle part according to claim 1,wherein plural apertures are formed in the backing plate, and each ofsaid apertures are located on the bending line.
 7. The vehicular partaccording to claim 6, wherein a size and number of the plurality ofapertures is determined so as to provide a desired section modulus ofthe backing plate.
 8. The vehicular part according to claim 1, whereinplural apertures are formed in the backing plate, some of said aperturesbeing located on the bending line while others of said plural aperturesare spaced from the bending line.
 9. The vehicular part according toclaim 1, wherein said at least one aperture has a circular shape. 10.The vehicular part according to claim 1, wherein said at least oneaperture has an oblong shape.
 11. The vehicular part according to claim1, wherein said at least one aperture has an elongated rectangularshape.
 12. The vehicular part according to claim 1, wherein said atleast one aperture comprises an irregularly profiled aperture.
 13. Thevehicular part according to claim 1, wherein plural apertures are formedin the backing plate, and said plural apertures are arranged in a zigzagpattern.
 14. The vehicular part according to claim 1, wherein pluralapertures are formed in the backing plate, and said plural apertures arearranged in parallel rows.
 15. The vehicular part according to claim 1,wherein plural apertures are formed in the backing plate, and saidplural apertures are arranged in a lattice pattern.
 16. A vehicular partcomprising: a blank material formed from a sheet metal and having a bentportion; and a backing plate joined with the blank material and having abent portion corresponding in position to, and bent along a same bendingline as, the bent portion of the blank material, the backing platefurther having at least one aperture formed therein at the bent portionthereof and located on the bending line, and wherein the backing platebent portion and the blank material bent portion are in intimate contactwith one another.
 17. The vehicular part according to claim 16, whereinthe vehicular part is an inner skin forming part of a hood of a vehiclebody, and the blank material forms the inner skin.
 18. The vehicularpart according to claim 17, wherein the inner skin has opposite sideedge portions extending in a longitudinal direction of the vehicle body,and the backing plate is disposed on each of the side edge portions. 19.The vehicular part according to claim 16, wherein a size of the apertureis selected so as o provide a desired section modulus of the backingplate.
 20. The vehicular part according to claim 16, wherein pluralapertures are formed in the backing plate, and each of said aperturesare located on the bending line.
 21. The vehicular part according toclaim 20, wherein a size and number of the plurality of apertures isdetermined so as to provide a desired section modulus of the backingplate.
 22. The vehicular part according to claim 16, wherein pluralapertures are formed in the backing plate, some of said apertures beinglocated on the bending line while others of said plural apertures arespaced from the bending line.
 23. The vehicular part according to claim16, wherein said at least one aperture has a shape selected from thegroup consisting of circular, oblong, elongated rectangular, andirregularly profiled.
 24. The vehicular part according to claim 22,wherein said plural apertures are arranged in a pattern selected fromthe group consisting of zigzag, lattice and parallel rows.
 25. Avehicular part comprising: a blank material formed from a sheet metaland having a bent portion, the bent portion being solid and free fromaperture; and a backing plate joined with the blank material and havinga bent portion corresponding in position to, and bent along a samebending line as, the bent portion of the blank material, the backingplate further having at least one aperture formed therein at the bentportion thereof and located on the bending line.
 26. The vehicular partaccording to claim 25, wherein the vehicular part is an inner skinforming part of a hood of a vehicle body, and the blank material formsthe inner skin.
 27. The vehicular part according to claim 26, whereinthe inner skin has opposite side edge portions extending in alongitudinal direction of the vehicle body, and the backing plate isdisposed on each of the side edge portions.
 28. The vehicular partaccording to claim 25, wherein a size of the aperture is selected so aso provide a desired section modulus of the backing plate.
 29. Thevehicular part according to claim 25, wherein plural apertures areformed in the backing plate, and each of said apertures are located onthe bending line.
 30. The vehicular part according to claim 29, whereina size and number of the plurality of apertures is determined so as toprovide a desired section modulus of the backing plate.
 31. Thevehicular part according to claim 25, wherein plural apertures areformed in the backing plate, some of said apertures being located on thebending line while others of said plural apertures are spaced from thebending line.
 32. The vehicular part according to claim 25, wherein saidat least one aperture has a shape selected from the group consisting ofcircular, oblong, elongated rectangular, and irregularly profiled. 33.The vehicular part according to claim 31, wherein said plural aperturesare arranged in a pattern selected from the group consisting of zigzag,lattice and parallel rows.